1. Field of the Invention
The present invention relates to beds generally. In particular, the invention relates to a mattress therefor and its method of manufacture.
2. Description of the Related Art
Beds and mattresses have been used for ages, but sleeper sofas with foldable mattresses were developed only in the first half of the twentieth century. Springless sleeper sofa mattresses were first developed by the Englander Co., Inc. of Chicago, Ill., in the late 1950s and are exemplified by U.S. Pat. No. 3,019,456 which was issued to Ewald Kamp on Feb. 6, 1962.
Mattresses made out of multiple layers of different plastic materials were first developed in the late 1960s and were fashionable until about 1990. Such multi-layered plastic mattresses are typified by U.S. Pat. No. 3,608,106 which was issued to Parramon on Sep. 28, 1971, and by U.S. Pat. No. 4,316,298 which was issued to Russo et al. on Feb. 23, 1982. In England, such mattresses are typified by British Patent Specification No. 1,257,962 published on Dec. 22, 1971, and by British Patent Specification No. 1,604,401 published on Dec. 9, 1981.
About 1990, the bedding market began to diversify with a variety of new springless mattresses, such as the following: compactible futons, exemplified by U.S. Pat. No. 4,928,337 issued to Chauncey on May 29, 1990; multiple component mattresses with removable covers, exemplified by U.S. Pat. No. 5,136,741 issued to Balonick et al. on Aug. 11, 1992; mattresses with impermeable PVC coatings, exemplified by U.S. Pat. No. 5,265,294 issued to McClure et al. on Nov. 30, 1993; and mattresses with temperature sensitive top layers, exemplified by U.S. Pat. No. 5,669,094 issued to Swanson on Sep. 23, 1997.
Other springless mattresses of general interest are shown in U.K. Patent Application Ser. No. 2,244,000 published on Nov. 20, 1991; U.S. Pat. No. 5,819,349 granted to Schwartz on Oct. 13, 1998; and U.S. Pat. No. 5,966,759 granted to Sanders et al. on Oct. 19, 1999.
However, it remains a problem in the prior art to make a springless foldable mattress which provides a comfortable night of sleep on a sofa bed.